Nanomaterials in architecture for green energy conversion and/or storage provide a desirable approach to alleviate environmental and energy issues. Titanium dioxide (TiO2) is regarded as one of the ideal candidates for high-rate anode materials, owing not only to its structural characteristics and special surface activity, but also to its low cost, safety, and environmental benignity.
However, the problem is the lack of open channels in bulk TiO2 which restricts its capacity and rate capability for reversible lithium insertion and extraction. A reduction in the effective size and construction of open channels in the material are the main strategies currently employed to increase the rate performance. Significant efforts have been made on the fabrication of anatase TiO2 nanosheets with exposed highly reactive (001) facets. Although the anatase framework undergoes insignificant structural distortion during lithium insertion and extraction, the rate of lithium diffusion is still limited by the narrow space of the host Ti—O lattice. For example, F− doped TiO2 nanosheets were proved to be good host structure for fast lithium insertion/extraction, due to its large exposed effective area and a short diffusion path. Unfortunately, strongly corrosive NaOH, HCl or HF solutions, which are very harmful to the environment, were used to obtain these desired materials. There is also potential danger in the high-temperature and high-pressure process in low boiling point inflammable solvents. Hence, it is an urgent task and challenge to synthesize novel TiO2 framework by a facile and clear route.
There is therefore a need for an improved method to prepare TiO2 nanostructures.